Numerous tools and techniques have been developed for repair of damaged plate glass surfaces, especially those made of laminated "safety" glass such as is used in automotive windshields. The cost benefit of repairing small cracks rather than replacing an entire windshield to restore the visual integrity of the windshield is substantial. Often, windshield damage, such as that caused by impact from small rocks or gravel, is in small chips, cracks, "bullseyes" and "stars" which may be confined to a small area. The common methods of repairing such small areas have involved variations of the basic steps of (1) providing an airtight seal around the broken area (2) drawing a vacuum to remove air from the broken area and (3) introducing a suitable ultraviolet curable liquid resin into the broken area under either ambient atmospheric pressure or under a positive pressure.
However, such methods are not readily suited to repair of more extensive damage in the form of elongated cracks. While such cracks may be created as a result of impact, more commonly a crack may spread over time from smaller localized areas of damage as the result of stress created by, for example, temperature induced expansion and contraction of the glass or mechanical vibration.
In such glass repair, the success of the repair, both structurally and visually, may be primarily dependent on the extent to which the damaged area is filled with repair resin without leaving voids or air bubbles within the repaired area. In order to repair a long crack, the primary method of repair has been for a technician to manually position a resin injector over the crack and manually guide the injector along the length of the crack while feeding resin into the crack. Mechanical means is often used to flex the glass slightly to open the crack and facilitate the penetration of repair resin.
Prior art methods of crack repair have typically involved using a guide for an injector wherein the supporting structure for the guide is moved as a unit along the windshield surface to follow a crack in the glass. Because of the movement of the supporting structure, such a system necessarily creates varied stresses upon the glass and can create some degree of relative movement between the edges of the crack. Such excessive movement of the glass may also result in further damage to the glass or may cause variations n the volume of the damaged area to be filled with resin, thereby promoting entry of air into the repaired area and resulting in a poor quality repair by affecting the degree to which the crack may be completely filled. By providing a stationary support for a movable injector, the present invention allows easily controlled movement of a resin injector over the glass surface and minimizes any stress or movement of the glass. This results in minimizing the spread of the damage to the glass, helps insure complete filling of a crack with repair resin, and makes the repair process quicker and easier with more a consistent outcome.
Additionally, the present invention provides a means of maintaining consistent contact between the injector tip and the crack opening while allowing relatively free movement of the injector along the crack. Because of the need to accurately guide the injector along the crack while simultaneously maintaining contact between the injector tip and the crack opening, the prior art methods and systems of crack repair have typically required that the technician be relatively skilled or experienced to effect an acceptable repair. In contrast the present invention is intended to provide an injector guide system in which the device maintains contact between the injector tip and the crack opening without hindering the freedom of movement of the injector to follow the path of the crack, even when used by a relatively less skilled operator.